DTC B1012 Battery Backup Power Supply

DTC DETECTING CONDITION:

Voltage failure caused by poor contact of battery power supply backup circuits

TROUBLE SYMPTOM:

Illuminations for the keyless entry, map light, luggage light, trunk light, room light, and ignition switch do not turn on.

NOTE: When B1011 «BATTERY P/SUPPLY MALFUNCTION CONT» is output at the same time, all the function of body integrated unit may not operate.

WIRING DIAGRAM:

Immobilizer system <Ref. to WIRING DIAGRAM , Immobilizer System.>

Fig 1: Battery Control Power Supply Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

Step	Check	Yes	No
1 CHECK DTC. Read the DTC of body integrated unit using Subaru Select Monitor. <Ref. to READ DIAGNOSTIC TROUBLE CODE (DTC) .>	Is DTC B1012 displayed? (Current malfunction)	Go to step 2 .	Go to step 5 .
2 CHECK DTC. Turn the ignition switch to OFF. Disconnect and then connect the body integrated unit connector. Wait approx. 2 minutes. Turn the ignition switch to ON. Read the DTC of body integrated unit using Subaru Select Monitor. <Ref. to READ DIAGNOSTIC TROUBLE CODE (DTC) .>	Is DTC B1012 displayed? (Current malfunction)	Go to step 3 .	Go to step 5 .
3 CHECK FUSE. Turn the ignition switch to OFF. Check the fuse.	Is the check result OK?	Go to step 4 .	Replace the defective fuse.
4 CHECK HARNESS. Disconnect the body integrated unit connector. Using the tester, measure the voltage between terminals. Connector & terminal (B281) No. 7 (+) - Chassis ground (-):	Is the voltage 8.5 - 16.5 V?	Replace the body integrated unit. <Ref. to Body Integrated Unit .>	Repair the harness between body integrated unit and fuse.
5 CHECK CONNECTOR. Turn the ignition switch to OFF. Disconnect the body integrated unit connector.	Is there poor contact of connector?	Repair or replace the poor contact of connector.	Even if DTC is displayed, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again. NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.